Katie Boulter was relieved to avoid being defaulted after inadvertently hitting a ball towards spectators during her US Open second-round win over Wang Yafan.

The British number one had just lost a 20-shot rally in the first set when a ball kid threw her the ball and she swatted it away, accidentally sending it spinning into a gangway in front of the crowd.

Had the ball hit a spectator Boulter would have been disqualified, but the chair umpire merely issued a code violation for ball abuse.

“Firstly, the safety of everyone is the most important thing for me,” she said. “It was completely unintentional, and luckily it wasn’t anywhere close to anyone.

“But for a second I was feeling pretty bad, if I’m honest.

“Of course there’s a lot of ifs. At the end of the day I’ve got to play with the facts. It didn’t (hit someone). It would be my worst nightmare, it really would. Completely unintentional, as well.

“Yeah, it was an unfortunate situation, but we moved through, and we managed to get a win.”

The 27-year-old went on to reach the third round at Flushing Meadows for the first time after a gutsy 5-7 6-1 6-4 victory over China’s Wang.

As well as the ball incident, in a tight first set Boulter retrieved an early break, and had three set points on the Wang serve.

But she was unable to convert any of them and Wang promptly broke to wrap up the set.

However Boulter, from Leicester, cleared her head impressively and dominated the second set to level the match.

Having broken again for 5-4 in the decider she suffered a horrible wobble, throwing in two double faults in the first three points.

But once again Boulter recovered her composure and wrapped up a fine win when Wang hit the net.

“I thought it was an absolute battle,” she added. “I worked really, really hard. I had a lot of chances in the first set. I didn’t quite get over the line.

“I think there were a few nerves, I’m not entirely sure why, but there were a few nerves in the first.

“After we finished that set I relaxed a bit and started to be a little bit more aggressive and it really paid off.”

There was disappointment, although not a major surprise, for Britain’s other remaining woman, Jodie Burrage.

The 24-year-old equipped herself well against second seed and Australian Open champion Aryna Sabalenka but bowed out 6-3 6-2 inside the Louis Armstrong Stadium.

“Obviously not the result I was looking for, but I had a pretty tough opponent,” said Burrage. “I thought she played really well today. She served really well, especially in the big moments.

“But I’m happy with how I played in a way and happy with how I was on the court.

“It’s a big occasion and you’re playing a big player like that. And I’m happy with the way I went about it. I didn’t feel out of place out there at all.”